H. Distler in Angew. Chem. 79 (1967) 520 gives a review of the preparation methods and properties of organic compounds containing S-alkylthiosulfate groups, hereafter referred to as Bunte salt groups. These synthesis methods are essentially based on reaction of reactive compounds, such as alkyl halides, epoxy-alkanes or alkenes, with an alkali metal thiosulfate in a polar medium. Since organosilicon compounds are insoluble or only slightly soluble in this medium, the described procedure cannot be applied without reservation to the preparation of organosilicon compounds containing Bunte salt groups.
Organosilicon compounds containing Bunte salt groups are already known. S. F. Thames and L. H. Edwards in J. Heterocyclic Chemistry 5 (1968) 115 describe, for example, the preparation of silanes containing N-substituted Bunte salt groups by reaction of halogenoalkyltrimethylsilanes with aminoethanethiosulfuric acid or vinyltrimethylsilane with ethyleneimine. According to DE 33 23 881 A1 l (Th. Goldschmidt AG; published on Jan. 10, 1985) and the corresponding U.S. Pat. No. 4,537,595 and DE 37 35 086 Cl (Th. Goldschmidt AG; published on Feb. 2, 1989) and the corresponding U.S. Pat. No. 4,895,917, organopolysiloxanes containing Bunte salt groups are prepared by reacting the corresponding epoxy-functional siloxanes with an alkali metal thiosulfate or ammonium thiosulfate. Since the epoxide ring is opened in this reaction, all the Bunte salt groups are bonded to the silicon over hydrocarbon spacers containing hydroxyl groups, which may have certain disadvantages in other applications or secondary reactions.
Therefore it is an object of the present invention to provide organosilicon compounds containing Bunte salt groups. Another object of the present invention is to provide a process for preparing organosilicon compounds containing Bunte salt groups.